Queen Elizabeth II Celebrates Her 90th Birthday

Her government and subjects are hosting gun salutes, fireworks and tributes in Parliament in her honour, and televised retrospectives are being broadcast of a royal life that has spanned from the Roaring Twenties to the Internet age.

The queen, born Princess Elizabeth on April 21, 1926, took the throne at 25 upon the death of her father, King George VI, in 1952. A majority of Britons have lived under no other monarch.

British Prime Minister David Cameron said the queen “has lived through some extraordinary times,” from World War II to the moon landing, the end of the Cold War and the advent of peace in Northern Ireland.

Cameron led tributes Thursday in the House of Commons to the monarch and her “unshakable sense of duty,” pointing out that the queen had provided counsel to 12 British prime ministers and met a quarter of all the U.S. presidents in history.

“Her Majesty has been steadfast — a rock of strength for our nation, for our Commonwealth and on many occasions for the whole world,” he declared.

At dusk, the Parliament building will be lit up in the red, white and blue of the Union Jack.

The queen is spending the day at Windsor Castle and will greet well-wishers on a walk through the town west of London. Hundreds have lined up hours beforehand, carrying cakes, cards, balloons and Union Jack flags.

The queen will receive more birthday greetings on Friday, when she hosts U.S. President Barack Obama and his wife Michelle Obama for lunch at Windsor Castle.